1. Field of The Invention
The present invention relates to a piston type compressor with a vibration-reducing suction valve mechanism, adapted for use as a refrigerant compressing unit to be incorporated in a refrigerating system or a climate control system. The refrigerating or climate control system may be used in an automobile.
2. Description of the Invention
Generally, a piston type compressor, such as a swash plate type compressor or a wobble plate type compressor, is provided with a cylinder block having therein a plurality of cylinder bores defined as compression chambers in which a plurality of pistons are reciprocated to compress a refrigerant gas. The piston type compressor further includes a valve plate or plates in which suction and discharge ports are bored to be in registration with the respective cylinder bores, suction and discharge reed valves arranged in contact with the surfaces of the valve plate to openably close the suction and discharge ports, and a housing or housings to close the axial end or ends of the cylinder block via the valve plate. The housing is arranged so as to define therein a suction chamber for a refrigerant gas before compression and a discharge chamber for the refrigerant gas after compression. The suction and discharge reed valves are brought into a close contact with the faces of the valve plate or valve plates when the respective valves close the suction and discharge ports, and are separated from the faces of the valve plate or plates when the respective valves open the suction and discharge ports. Further, the cylinder block is provided with stops arranged at end portions of the respective cylinder bores so that the free ends of the suction reed valves are engaged with and stopped by the stops when the respective suction reed valves move from the position closing the suction ports to the position opening the suction ports of the valve plate or plates. Namely, the amount of opening of the respective suction reed valves is restricted by the stops of the cylinder blocks, and the stops are usually formed in recesses provided by cutting a part of the end portion of a cylindrical wall enclosing each cylinder bore. Thus, the opening amount of each suction reed valve is determined by a depth of each recess formed in the cylindrical wall of each cylinder bore. Nevertheless, when the compressor operates at either an idling speed or a low rotating speed, and at a small delivery capacity, the flow of refrigerant gas throughout the refrigerating system including the compressor is sharply reduced. Thus, the amount of refrigerant gas from the suction chamber into the respective cylinder bores is very small, and accordingly, the free end portion of each suction reed valve cannot be sufficiently bent until the free end portion of the suction reed valve is certainly engaged with the recessed stop of the cylinder block. Consequently, the suction reed valves cause uncontrolled self-vibrating motions which generate noise.
On the other hand, when the depth of the respective recessed stops is set small, although the self-vibrating problem of the suction reed valves can be overcome, the amount of opening of the suction reed valves is necessarily made small. Accordingly, suction performance of the suction valve mechanism of the piston type compressor must be reduced.